Liquid trapping means for a film unit

ABSTRACT

FOR TRAPPING AND RETAINING THE EXCESS PROCESSING FLUID DISTRIBUTED BETWEEN AN EXPOSED PHTOTSENSITIVE SHEET AND A SECOND SHEET SUPERPOSED THEREWITH WHEN THE TWO ARE MOVED LONGITUDINALLY BETWEEN A PAIR OF PRESSURE APPLYING MEMBERS TO RUPTURE A POD CONTAINING AN AMOUNT OF PROCESSING SOLUTION IN EXCESS OF THAT REQUIRED TO PROCESS THE EXPOSED LATENT IMAGE, THE TRAILING END OF ONE OF THE SHEETS IS EXTENTED BEYOND THE IMAGE AREA THEREOF AND IS MEDIALLY FOLDED BACK UPON ITSELF TO PROVIDE A FLAP THE FREE END OF WHICH WILL EXTEND BACK AT LEAST TO THE TRAILING END OF THE OTHER SHEET, AND PROBABLY BEYOND AND UNDER THE TRAILING END OF THE OTHER SHEET, TO FORM A TRAP FOR THE EXCESS PROCESSING FLUID. THE SHEET WHOSE TRAILING END IS FOLDED BACK TO FORM THE TRAP SHOULD BE MADE OF MATERIAL HAVING SUFFICIENT RIGIDITY AND/OR RESILIENCE THAT IT RESISTS FOLDING SO THAT THE FREE END OF THE FOLDED-BACK FLAP NORMALLY REMAINS SPACED FROM THE SHEET PROPER TO FROM AN OPEN MOUTH FOR RECEIVING EXCESS PROCESSING FLUID. THE LONGITUDINAL EDGES OF THE FOLDED-BACK TRAP ARE SEALED TOGETHER IN SUCH A WAY AS TO PREVENT THE FLOW OF PROCESSING FLUID FROM THE EDGES BUT TO ALLOW THE ESCAPE OF AIR THEREFROM. AT LEAST ONE PROTUBERANCE IS EMBOSSED IN EACH OF THE SEALED EDGES TO EFFECT A SIGNIFICANT SEPARATION OF THE PRESSURE APPLYING MEMBERS AS THE TRAP PASSES THEREBETWEEN WHEREBY THE FOLDED-BACKED FLAP WILL NOT BE COMPRESSED SUFFICIENTLY TO CAUSE A BACK FLOW OF ANY FLUID WHICH HAS ENTERED THE TRAP.

5. R. SCHIEVEN LIQUID TRAPPING MEANS FOR A FILM UNIT Sept. 5, 1972 Filed Jan. 7, 1971 3 Sheets-Sheet 1 deceased by ARL/NE E. SCH/EVEN EXECUTE/X 75 Fla. 8

STANLEY R SCH/EVEN INVENTOR. M&%M

A TTORNEYS P 5, 1972 s. R. SCHIEVEN 3,689,269

LIQUID TRAPPING MEANS FOR A FILM UNIT Filed Jan. 7, 1971 5 Sheets-SheetB & Q R, 200

STANLEY R SCH/EVEN ARL/NE E. SCH/EVEN EXECUTE/X INVENTOR.

A T TOR/V5 Y5 deceased b y United States Patent fice Patented Sept. 5, 1972 3,689,269 LIQUID TRAPPING MEANS FOR A FILM UNIT Stanley R. Schieven, deceased, late of Webster, N.Y., by Arline E. Schieven, executrix, Webster, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y.

Filed Jan. 7, 1971, Ser. No. 104,713 Int. Cl. G03c 1/48 U.S. Cl. 96-76 C 8 Claims ABSTRACT OF THE DISCLOSURE For trapping and retaining the excess processing fluid distributed between an exposed photosensitive sheet and a second sheet superposed therewith when the two are moved longitudinally between a pair of pressure applying members to rupture a pod containing an amount of processing solution in excess of that required to process the exposed latent image, the trailing end of one of the sheets is extended beyond the image area thereof and is medially folded back upon itself to provide a flap the free end of which will extend back at least to the trailing end of the other sheet, and probably beyond and under the trailing end of the other sheet, to form a trap for the excess processing fluid. The sheet whose trailing end is folded back to form the trap should be made of material having sufficient rigidity and/or resilience that it resists folding so that the free end of the folded-back flap normally remains spaced from the sheet proper to form an open mouth for receiving excess processing fluid. The longitudinal edges of the folded-back trap are sealed to gether in such a way as to prevent the flow of processing fluid from the edges but to allow the escape of air therefrom. At least one protuberance is embossed in each of the sealed edges to effect a significant separation of the pressure applying members as the trap passes therebetween whereby the folded-back flap will not be com pressed sufficiently to cause a back flow of any fluid which has entered the trap.

The present invention relates to photography, and more particularly to a novel photographic product for obtaining a positive print by an image transfer process.

In photographic difiusion transfer processing, the photosensitive sheet element is normally first exposed and then biased into superposed relation with a second sheet element which is, in general photographically inert and aids in the controlled distribution of the processing fluid between the two. The photosensitive element may contain an integral print receiving stratum or, most preferably, the second sheet element comprises a transfer image-receiving element. After the photosensitive sheet has been photographically exposed, the two sheet elements are biased into face-to-face relation and moved relative to, and between, a pair of opposed pressure-applying members, such as a pair of parallel rollers which are spring loaded toward rolling engagement with one another. Application of pressure to a frangible fluid retaining means situated between the sheet elements adjacent their leading ends effects a controlled rupture thereof and a predetermined unidirectional distribution of its processing fluid contents therebetween, and in contact with, the opposed surfaces of the superposed sheet elements. Subsequent to transfer processing, the image carrying area of the print-receiving sheet may be separated from the laminate.

In order to insure that the predetermined area to be processed is completely covered with a layer of predetermined thickness, it is generally necessary to supply an amount of processing fluid in excess of the minimum amount required to provide these desired parameters. For this reason, and because this processing fluid is highly caustic, some means must be provided to trap and retain the excess fluid which remains after distribution of the processing fluid in order to prevent its undesired escape from the lamination within and also outside of the camera apparatus.

In order to trap this excessive processing fluid within the laminated photosensitive and image-receiving elements it has been taught, see U.S. Pats. 2,644,755 and 2,686,717, that the trailing portions of the respective sheet elements may have one or more spacing elements or lifters made of some rigid material, e.g. hard rubber, plastic, etc., adhered to the surface adjacent the trailing end of one of the sheet elements. As the trailing portions of the sheet elements are drawn between the pressureapplying members in superposed relation during the distribution of the processing fluid, the spacing elements, or lifters, force the pressure-applying members apart. The excess processing fluid, rather than being further advanced, is thus collected and retained in the space formed between the superposed trailing portions of the sheet elements. In an effort to reduce the size of the trap required with film units designed for use in film packs, U.S. Pat. 3,294,538 suggests forming a positive trap by folding the end of the receiver sheet upon itself and interposing a spring member bet-ween the folded-over end of the sheet element and the main body of the sheet element to maintain the two separated so that the excess fluid can readily enter the trap.

As will be appreciated from the above description, the heretofore proposed excess fluid trapping means have required the attachment of lifters and/ or springs to the film units. Such constructions not only complicate the fabrication and handling of a film product in a camera, but it has been found that these lifters have a tendency to become accidentally detached from their sheet element during the handling of the film unit outside of the camera or during manipulation within the camera. If the lifters become detached before the film product is processed, then they are not available to serve their intended function in the trapping of the excess fluid. Furthermore, if these lifters become detached from their sheet element for any reason during manipulation of the film in the camera they can shift from their intended position and even move up into the image area of the elements and prevent proper transfer of the image from the photosensitive sheet to the image-receiving sheet.

In copending U.S. patent application S.N. 841,865 of which I am a coinventor, there is disclosed and claimed a trap construction which overcomes the disadvantages of those heretofore mentioned in that no lifters or other parts which may become accidentally detached from the film product before or during its use. In this last mentioned trap construction the trailing end of one or both of the sheet elements has a plurality of protuberances embossed from its surface to separate the opposite surfaces and hold them separated as they pass between the pressureapplying members and thereby provide a space in which the excess processing fluid can collect. Since each protuberance is readily compressible, a plurality of them must be provided distributed over a substantial area to effect a significant separation of the pressure-applying members. While this last mentioned trap construction in effect provided lifters for the pressure-applying members which are part of the film product and could not become accidentally detached therefrom, because of the number of protuberances required across the width of the trap its capacity was restricted somewhat. While such a trap has sufficiently capacity for processing black and white film, it was found difficult, if not impossible, to increase its capacity to accommodate color films 'which require approximately twice the volume of processing solution as black and white film. There is a limit to the extent that a sheet of material can be drawn during an embossing operation without rupturing, and the deeper the protuberances are drawn the more compressible each one is. Accordingly, while one might except that the capacity of the embossed trap described might be increased by making the protuberances higher, this does not follow since then more protuberances are then required to separate the pressure-applying members because the deeper the protuberances are drawn the more readily each one is compressed.

The primary object of the present invention is to provide in a film unit comprising, in combination, a first photosensitive sheet element, a second sheet element, and a rupturable container adapted for unidirectional release of a retained fluid processing composition for selective distribution between and in contact with opposed surfaces of said first and second sheet elements, a new and novel trap means on the trailing end of at least one of said sheet elements adapted to trap or retain any processing fluid which is in excess of that required to be spread between the sheet elements and which overcomes the disadvantages and/or the limitations of the trap means of the prior art.

Other objects of the invention are to provide a trap means on the trailing end of one of the sheet elements of a film unit of the type referred to which (1) minimizes the amount of separation of the pressure-applying means thereby minimizing the force required to extract the film unit from the camera; (2) has a greater capacity than known trap means; (3) has the lifters for the pressureapplying members integral with the trailing end of one of the sheet elements of the film rather than requiring the adhesive attachment of them to the trailing end of one of the sheet elements so that they are apt to become accidentally detached therefrom before or during processing of the film unit; and (4) a trap which permits the escape of entrained air therefrom.

The novel features that I consider characteristic of my invention are set forth with particularity in the appending claims. The invention itself, however, both as to its organization and its methods of operation, together with additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of a photographic film unit of the film pack type embodying a trap constructed in accordance with a preferred embodiment of the present invention;

FIG. 2 is a plan view of the film unit of FIG. 1;

FIG. 3 is a perspective view of a film pack comprising an assemblage of film units of the type shown in FIGS. 1 and 2;

FIG. 4 is an enlarged longitudinal section taken substantially midway between the sides of the pack shown in FIG. 3;

'FIG. 5 is an exaggerated perspective view of the trailing end of a film unit showing the relationship of the film, receiver and trap when the film and receiver are superposed for processing;

FIG. 6 is an enlarged plan view of the trap constructed in accordance with the present invention;

FIG. 6A is a schematic plan view showing how the excess fluid enters the trap;

FIG. 7 is an enlarged sectional detail taken on line 77 of FIG. 5;

FIG. 8 is an enlarged sectional detail showing a film unit passing between pressure-applying rolls of a camera and just before the trap at the end 'of the film unit passes between said pressure-applying rolls;

FIG. 9 is a view similar to FIG. 8 but showing the film unit advanced to the point where the trap is between the pressure-applying rolls and the rolls are separated by the protuberances at the end of the trap to prevent them from pressing upon the filled trap and causing a back flow of the fluid received in the trap;

FIG. 10 is a view similar to FIG. 9 but showing the film unit in elevation to illustrate how the protuberances on the trap separate the pressure-applying rolls; and

FIG. 11 is a schematic, fragmentary, isometric view showing a trap constructed in accordance with the present invention applied to an image-transfer film product of the roll type.

Photographic products for obtaining a positive print by a one-step, image-transfer process can be made in two forms, (1) individual film units for use in packs, or (2) a roll type product, a novel liquid trapping means constructed in accordance with the present invention is adaptable to both of these forms of product. These two forms of product are alike in that in each the components for producing a positive image include a sheet of photosensitive material (film) adapted to be photographically exposed to produce a latent photographic image; and a second or print-receiving sheet (receiver) for receiving a positive transfer image; a rupturable container or pod of a fluid agent for reacting with the photosensitive sheet after its exposure to produce the positive image on the second sheet when distributed between the two sheets as they are moved between a pair of pressure-applying members in superposed relation; and trapping means on the trailing end of one or both of said sheets for receiving and retaining any excess fluid agent reaching the ends of the sheets as they are pulled from between the pressureapplying members. The film pack and roll product differ from each other primarily in the physical arrangement of the noted individual components which affects the manner in which they are manipulated in a camera to bring the first and second sheets into superposed relation after ex posure of the first sheet and before they are passed between the pressure-applying rollers to capture the fluid containing pod and spread the processing fluid contained therein between the adjacent surfaces of the two sheets. For use in a film pack the two sheets are arranged so that the photosensitive sheet may be photographically exposed and the two sheets are coupled by a leader means by means of which the sheets can be withdrawn from the pack in superposed relation and then through the pressureapplying rollers of the camera to rupture the fluid container and spread its processing fluid unidirectionally between the sheets. A film pack may contain a plurality of these film units which can be individually exposed and processed in succession.

In the roll type product, on the other hand, a plurality of photosensitive areas are spaced along a continuous strip of material supplied in roll form. A like number of printreceiving areas are spaced along a strip of material also supplied in roll form. A rupturable container of processing fluid is fixed to one or the other of the strips, usually the one carrying the print-receiving areas, and ahead of each print-receiving area thereon. These two rolls of photosensitive and receiver sheets may be used in a camera of the type shown in US. Pat. 2,644,755 in which the strip of photosensitive material is moved into the focal plane to be photographically exposed and thereafter is superposed with a corresponding receiver sheet or the strip of receiver material before being passed between a pair of pressure-applying rolls to rupture the container of processing fluid associated with the leading end of the receiver sheet and to spread the fluid between the superposed photosensitive and receiver sheets.

It will be appreciated that in a photographic product of the type to which the novel trapping means of this invention relates, there are two sheets, a photosensitive sheet and an image-receiving sheet or a second sheet which serves only as a means of confining a layer of processing fluid on the exposed photosensitive sheet. In use, a processing liquid is dispensed in some manner, e.g. from a rupturable container or pod adjacent the leading end of the image area, between the two sheets which are superposed before, or just as, the processing fluid is dispensed therebetween. After the processing fluid is dispensed between the sheets, it is spread between them by pressureapplying means which are moved relative to the product from the end at which the fluid has been dispensed toward the opposite end. In order to insure proper coverage of the entire image area of these two sheets an excess of processing liquid is used. In order to prevent the excess liquid from contaminating the spreading means of the camera or the customers hands, trapping means is provided at the trailing end of these sheets to collect and confine the excess processing fluid. According to the present invention, the trailing end of one of these sheets is extended beyond the image area thereof and is medially folded back upon itself to provide a flap the free end of which will extend back at least to the trailing end of the other sheet, and preferably beyond and under the trailing end of the other sheet, to form a trap for the excess processing fluid. The sheet whose trailing end is folded back to form the trap should be made of a material having sufficient rigidity and/or resilience that it resists folding so that the free end of the folded-back flap normally remains spaced from the sheet proper to form an open mouth for receiving excess processing fluid. Paper of the type from which tabulating cards are made or certain thicknesses of plastic material e.g. .005 thick polyester, polystyrene, polycarbonate, etc. will have the necessary resilience and/ or rigidity mentioned so that if the sheet on the trailing end of which the trap is to be formed is made of one of these or like materials then the trailing end thereof can be folded back to make the trap. If one of the sheets does not have the above-mentioned physical characteristics then an elongated trailer sheet of the desired material can have its leading end attached to the trailing end of one of the superposed sheets and be medially folded to form a trap as above described.

The longitudinal edges of said folded-back trap are then sealed together to prevent the flow of processing fluid from said edges and to form a pocket having an open mouth for receiving the excess processing liquid. Because of the resilient and rigid characteristics of the material from which the trap is made, when its longitudinal edges are sealed that portion of the folded-back flap will tend to bow away from its opposite surface attached to the end of the sheet so as to provide an open mouth for the trap. At least one protuberance is embossed from each of the sealed edges of the trap to act as lifters for the pressure-applying rolls of the cameras and effect a significant separation of the rolls as the trap passes between the rolls whereby the flap of the trap will not be pressed down sufliciently to cause a back flow of any processing fluid which has entered the trap. It has been found that an embossing made in the double thickness of the sealed edges of the trap is sufliciently non-compressible to act as lifters and effect the desired separation of the pressureapplying rolls of the camera. As a result, the entire length of the trap between the sealed edges is left unobstructed to receive excess processing fluid and consequently the capacity of the trap is increased as compared to those having a plurality of embossings in a single thickness of the trap and spaced completely across the trap, as disclosed in copending patent application S.N. 841,865 filed July 15, 1969 of which I am a coinventor.

It has been found that if the free end of the folded-back flap of the trap is bent up slightly along a line spaced slightly behind and parallel to the leading edge thereof that the trap will have a flared or funnel shaped open mouth which enhances the reception of excess processing fluid and the tendency of the flap to bow open. It has also been found that the capacity of the trap will be increased if provision is made for the escape of air which might become entrained in the trap. Provision for the escape of entrained air from the trap can be made in either of two ways. One way is to make the seals along the longitudinal edges of the trap in an interrupted fashion such that openings are provided which are so small that the processing fluid, which is quite viscous, will not leak therethrough but air will. The second way is not to make the longitudinal seals extend the full depth of the flap but 6 extend only from the fold to a point short of the mouth of the trap. It has been found that since the front of the processing fluid moving into the trap takes the form of a V having an arcuate vertex any air pushed ahead of it- Will have a chance to escape from the unsealed portions of the edges adjacent the mouth before these areas of the trap are filled with processing fluid. A trap of this type also allows the use of the image-receiving sheet restraint means disclosed in copending patent application S.N. 841,- 864, filed July 15, 1969 having the same assignee as this application.

Reference is now made to FIGS. 1-4 where there is illustrated a pack type film unit having a trapping means constructed in accordance with a preferred embodiment of the present invention and an assemblage of such film units in the form of a film pack. Each film unit designated 10 comprises a generally rectangular photosensitive sheet or film 11 and a second or print-receiving sheet 12. Both of these sheets comprise a support which is opaque to light actinic to the photosensitive coating of the film. The photosensitive coating comprises a layer of any conventional photographic recording media, gelatino silver halide emulsions being preferred, coated on a light-opaque, flexible sheet such as paper, organic plastics, etc.

The second, or print-receiving sheet 12 may merely serve to aid in the distribution of a processing fluid in contact with the photosensitive layer of film 11, or, in the preferred form of the film unit, comprises means for supporting a transfer image formed, for example, by a silver halide diffusion, transfer reversal process. Attached to the leading edge of the film 11 is a leader sheet 14 having a tapered end section 16. The transverse edge of leader 14 is coupled to the leading edge of the film 11 as indicated at 17 and a rupturable fluid containing pod 18 is mounted on the leader 14 ahead of the leading end of the film 11. The second or print-receiving sheet 12 is mounted on a carrier sheet 19 having an intermediate section 20 approximately equal in width to the receiver 12 and having a generally rectangular opening 21 therein defining the area of the receiver sheet 12 in which the image formation occurs. Those portions of the intermediate section 20 bordering on opening 21 provide a mask for defining the area of the image transferred from the film 11 to the receiver sheet 12. Mounted on the narrow portion of the carrier sheet extending along the lateral edges of the receiver sheet are spacer rails 13, which in combination with the mask portion of carrier sheet 19, determine the thickness of the processing fluid spread bet-ween the film 11 and receiver 12 as will be more fully set forth below. Carrier sheet 19 includes a leading end section 23 having a tapered end section 24 similar to the tapered end section 16 and secured thereto behind the leading end of the tapered end section 16 as indicated at 17. Tapered end sections 16 and 24 cooperate to define the leading end section of the film unit which is advanced between pressure-applying members for processing of the film unit.

The length of the leader sheet 14 between the leading edge of the film 11 and the point of attachment of the leader sheet to the carrier sheet 19 is substantially equal to the length of the carrier sheet between its point of attachment to the leader sheet 14 and the leading edge of the receiver 12. It is by virtue of this arrangement that the film 11 and receiver 12 are capable of being biased into superposed registered relation during the processing of the film unit.

In the preferred embodiment of the present invention the trapping means for the excess processing liquid is associated with the trailing end of the receiver 12 of the film unit. To this end the trap 25 is shown as comprising a trailer sheet 26 secured to the face of the trailing end of the carrier sheet 19 which extends slightly beyond the end of the receiver 12 as indicated at 19. The width of the trailer sheet is substantially equal to the width of the carrier sheet 19 and the film 11. The trailer sheet 26 is medially folded back upon itself to provide a flap 27 the free end of which extends back over the trailing end of the carrier sheet 19 to a point where it will lie under the trailing end of the film 11 when the film 11 and receiver sheet 12 are biased into superposed registration, see FIG. 8. Preferably, the trailer sheet 26 is of such length that when its flap 27 is pressed down against the carrier sheet 19 the free end of the flap 27 will substantially butt with the ends of the spacer rails 13 on the carrier sheet, see FIG. 9. The trailer sheet 26 is made of a material which has suflicient rigidity and/ or resilience that it resists folding so that the free end of the flap normally remains spaced from the carrier sheet 19 to form an open mouth for receiving excess processing solution. To this end, the trailer sheet 26 from which the trap is formed may be made from any number of different materials, e.g. paper of the type used in tabulating card stock, plastic sheets including .005 thick polystyrene, polycarbonate, polyester, etc. It will be apparent that if the film 11 and/or receiver 12 is made of a material having this desired resilient characteristic then the trap 25 could be made by folding back the trailing end of either one of these elements rather than adding a separate trailer sheet 26 to the end thereof. Likewise, it will be apparent that the trailer sheet 26 could be attached to the trailing end of the film 11, rather than to the trailing end of the receiver 12 as disclosed, without going beyond the scope of the present invention. In order to keep the thickness of the film unit at a minimum, and to enhance the tendency of the free end of the flap 27 to spring open, it has been found desirable to crease the fold line of the trap.

The longitudinal edges of the trap are sealed together as illustrated at 30, FIG. 6, to prevent the excess processing fluid from leaking out the edges. These sealed edges are then embossed to provide one or more protuberances 28 which extend above the surface of the trap and act as lifters for the pressure rolls of the camera as will be hereinafter described. It has been found that these protuberances, because they are formed from a double thickness of the trap material, are sufficiently non-compressible so that as the trap moves between the pressure rollers of the camera, as shown in FIG. 10, they will separate the rollers and prevent them from pressing on that section of the trap between the sealed edges to cause a back flow of the excess processing solution fed into the trap. Rather than being in the form of a plurality of dimples as shown, these protuberances can take the form of ridges which extend longitudinally of sealed edges. These protuberances 28 do the same job as separate lifters used in the prior art but have the advantage that they do not require the attachment of separate parts to the film unit which can become accidentally detached therefrom before or during use of the product. This arrangement of protuberances has the advantage over that shown in the above-noted copending patent application S.N. 841,865 for the reason that they are sulficiently non-compressible that they are needed only at the ends of the trap, instead of being spaced across the entire width of the trap. The result is that the capacity of the trap is greatly increased.

The capacity of the trap 25 will be further increased if provision is made for the escape of air which may be entrained therein as the result of air being pushed ahead of the processing fluid as the superposed film 11 and receiver 12 is moved between the pressure rolls of the camera. One way in which this may be accomplished with the present trap is to interrupt the longitudinal seals of the trap at one or more points along their lengths, as shown in FIG. 6. The interruption in the seals are made so small that air may escape therethrough but the processing solution, which is quite viscous, will not pass therethrough. A second and preferred, way of providing for the escape of entrained air from the trap comprises stopping the edge seals short of the free end of the flap 37 as indicated at in FIG. 6A. Inasmuch as the excess processing fluid entering the trap has a tongue-shaped front as indicated at 100 in FIG. 6A any air which is pushed into the trap ahead of the fluid will move up the sealed edges to escape from the unsealed portion thereof adjacent the free end of the flap, see directional arrows 101, thus allowing the fluid to spread out and fill the full width of the trap. The dimensions of the portion of the trap bounded by the fold and the sealed edges is such that the excess fluid will be confined thereby and none will extend out toward the open mouth so far as to leak from the unsealed portions of the trap edges. To improve the receptiveness of the open mouth of the trap the free edges of the flap 27 thereof may be flared up as shown at 27. This flared, or bent up edge of the flap 27 aids in keeping the mouth of the trap open to receive excess processing fluid and also provides a funnel type entrance to the trap. If the trap is made of a material having the rigid and/ or resilient characteristics mentioned above, when it is medially folded and sealed at the edges as described the flap will have a tendency to bow away from the receiver 12 and keep the mouth of the trap open, as illustrated most clearly in FIGS. 5 and 6.

Distribution of the processing fluid is eflected by advancing the film 11, receiver 12 and pod 18 in superposed relation between a pair of juxtaposed pressureapplying rollers and 76 forming a part of the camera in which the film unit is exposed. The rollers are mounted in such a manner, not shown, that one is spring loaded toward rolling contact with the other and as a result a compressive pressure is applied by them to the sheets 11 and 12 progressively, from the leading end in the area of the pod to the trailing ends, to cause ejection of the fiuid contents of the pod between the sheets and the spreading of the fluid in a layer between and in contact with the sheets. The superposed spacer rails 13 and longitudinal margins of the mask portion of the carrier sheet 19 keep the processing fluid from leaking out at the edges of the film unit and their combined thickness determines the thickness of the layer of processing fluid which is spread between the image areas of the film and receiver sheets 11 and 12, respectively. The excess of processing fluid, which is always provided in the pod, is effectively collected and retained at the trailing end of the film unit by the trap means 25 the mouth of which stays open to receive said excess fluid until the trap per se moves between said rollers, at which time the embossed protuberances 28 at the sides of the trap serve as lifters to separate the rollers and prevent them from compressing the filled trap to cause a back flow of processing fluid from the trap. FIGS. 8 and 9 show the relationship of the film 11, receiver 12, carrier sheet 19 and trap 25 just as the trailing end of the film unit is approaching the pressure rollers 75 and 76 of a camera and as the trap is passing through said rollers, respectively. It will be appreciated that the thickness dimensions of the film, receiver, trap and layer of processing solution are exaggerated for purposes of clarity.

A film pack or assemblage of film units 10 is shown in FIGS. 3 and 4. The film pack comprises a generally parallelepiped-shaped container or box 39 for holding and enclosing a plurality of film units 10 when each is folded upon itself as generally indicated in FIG. 1. Container 39 comprises two sections, a forward section having forward walls 40, side walls 41, a trailing end wall 42 and a leading end wall 43. Forward wall 40 is provided with a generally rectangular exposure aperture 44 for exposing the film 11 of the film units carried within the container. Leading end wall 43 extends only part way of the depth of the container to provide a passage 45 at the leading end of the container through which the film units can be withdrawn from the container one at a time. The rear section of the container comprises a metal cover 46 having flanges 47 turned down along its sides and rear and to slidably engage the side walls 41 and trailing end wall 42 of the container when the cover is slid endwise onto the container.

The arrangement of each film unit within the container 39 is illustrated in FIG. 1, and the arrangement of a plurality of film units (only two being shown for purposes of clarity) is illustrated in FIG. 4. Each film unit is arranged with the film 11 and receiver sheet 12 in overlying relation with the photosensitive surface of the film 11 outward toward exposure aperture 44, and with the surface of receiver 12, which is superposed therewith during processing, facing inwardly in the same direction. That portion of the leader sheet 14 between the leading edge of the film 11 and the pod 18 is bent back upon itself, and carrier sheet 19 is similarly bent back upon itself adjacent to the leading edge of receiver 12 so that portions of the leader sheet 14 and carrier sheet 19 lie between the film 11 and receiver 12, and the leading and trailing ends of the film 11 are disposed adjacent, respectively, to the trailing and leading ends of the receiver 12. The film pack is provided with a generally flat rectangular pressure plate 50 located intermediate to film 11 and the other portion of the film unit for supporting the film against the inner surface of the forward wall 40 in position for exposure through the exposure aperture 44. Pressure plate 50 includes a rolled end section 52 around which extends the bent-back portion of the leader sheet 14, see FIG. 4. Rolled end section 52 is provided for guiding film 11 around the end of the pressure plate and into superposed relation with its correspondin receiver in a manner to be described hereinafter. The major portion of the leader sheet 14, the pod 18 mounted thereon and the carrier sheet 19 are located behind the pressure plate 50 and between the latter and the receiver sheet 12. Pressure plate 50 is provided with lateral flanges 54 disposed adjacent to side walls 41 of the container. Looking at FIGS. and 6, one or both longitudinal edges of the trap 25 may be provided with extensions 200 which are adapted to engage the rear edge of these lateral side walls to restrain the receiver sheet 12 against accidental movement as its corresponding film unit is driven around into superposed registration therewith as disclosed in copending US. application S.N. 841,864 filed July 15, 1969. The cover 46 of the container is provided with spring fingers 54 biased inwardly for engaging the top of lateral flanges 54 and biasing pressure plate 50 toward forward wall 40 to retain the film 11 in a predetermined plane for exposure.

The means for putting the film 11 of a film unit into superposed registration with its receiver 12 after exposure of the film and for advancing the tapered end 16 of the leader 14 between the pair of pressure rolls of a camera so that it can be grasped comprises an elongated pull tab 60. This pull tab is adhesively secured at its trailing end to the tapered end section 16 of the leader 14 at a point behind the leading end of leader 14. The adhesive bond between the pull tab and the leader 14 is such that it will have sufficient shear strength to advance the film into registration with its receiver and also advance the tapered end of the leader 14 between the pressure rolls, but will peel away from the leader 14 when such movement of the film is accomplished, as well known in the art. After the pull tab 60 has become detached from leader 14 the film 11 is nearly in register with its receiver 12 and the leading end 16 of the leader 14 extends between the pressure rollers of the camera. Now to effect processing of the film unit the leading end of the leader is grasped and pulled from the camera. This completes registration of film 11 and receiver 12 and pulls the film unit from the camera with the exposed film 11 in superposed registration with its receiver 12 and causes rupture of the pod 18 and a spreading of the fluid therefrom between and in contact with the film and receiver as described above and as indicated in FIGS. 8-10. The film units incorporating the present invention and comprising film pack 38 are adapted for use in a hand held camera of the type shown in US. Pat. 3,080,805. Inasmuch as the camera per se and the manner in which the film pack cooperates therewith forms no part of the present invention only so much of the camera has been disclosed herein as is necessary to give a complete understanding of the utility and advantages of the present invention.

The liquid trapping means of the present invention is not limited to use on individual film units which are to be assembled in film packs, but is also adapted for use in film products for carrying out a one-step photographic process of the roll type such as shown in US. Pat. 2,644,- 755. In this roll type product the photosensitive layer comprises a continuous sheet of photosensitive material and the print-receiving layer comprises a continuous sheet of material suitable for forming the background for a positive image comprising silver. The print receiving material and the photosensitive material are coiled into separate rolls adapted to be arranged in a carrier so that successive areas of the photosensitive sheet can be individually exposed and then be superposed with successive image areas on the print-receiving material before the two are moved between pressure-applying rollers for processing of the film.

Referring to FIG. 11, there is shown a photographic product of the roll type incorporating a trap means constructed in accordance with the present invention as well as the manner in which this product is used. There is shown a photosensitive layer 11 with its photosensitive surface facing upwardly with an exposure image area indicated at 11a. The image area 11a is that area of the layer 11' which is in exposure position when a developer pod 18' on the print-receiving layer 12 is in a predetermined position with respect to the processing members of the camera. On that surface of the print-receiving layer 12' which is brought into face-to-face contact with the image area 110, there is shown a positive image 'area 12a, this area being roughly defined by the distance between a pair of developing pods 18'. This image area 12a is completely defined by a series of perforations 300 extending around the periphery thereof. For the purpose of trapping excess spread developer there is provided a trap 25 which, according to a preferred embodiment of the present invention, comprises a medially folded sheet of thermoplastic, or other material having sufficient resilience and/ or rigidity so that the flap 27 thereof tends to flex away from the base portion thereof. Trap 25 is adhered to the print-receiving surface adjacent to the rear end of each developer pod and with the open mouth thereof facing the pod 18 ahead. The base portion of the trap is entirely cemented to the print-receiving layer 12 and may have the end thereof adjacent to the open mouth of the trap feathered down to facilitate the entrance of excess processing solution into said mouth.

Also, shown in FIG. 11 is a pair of processing members which are schematically illustrated as pressure-applying rollers 75 and 76'. In a preferred form of camera, one of the pressure rollers 76' is fixedly mounted and the other is placed under a resilient load by means of a spring 105. For controlling the thickness of spread of liquid issuing from a pod 18' when it is ruptured there may be provided spacer rails 13' secured to the longitudinal marginal positions of the image receiving layer 12.

In the use of this roll type product in a camera designed therefor, the photosensitive layer 11' and the receiver layer 12' may be moved to the position indicated by pulling on the leaders and 111. A known type of metering mechanism, not shown, within the camera cooperating with the photosensitive and receiving layers, respectively, may be used to properly position the two layers in the position shown for making an exposure when the two layers are advanced by pulling the leader portions 110 and 111. After an exposure of the image area 11a is made, the two leader portions 110 and 111 are again pulled. During commencement of the pull, the passage of the pod 18' between the pressure rolls 75' and 76' increases the hydraulic pressure within the pod to the point where the liquid is forced out of the trailing edge of the pod. As the pull is continued, the liquid is spread between the two layers in a thin uniform layer having a thickness as defined by that of the spacer rails 13, the liquid acting l. l to bond the photosensitive and image-receiving layers together as a unit and to carry out the formation of the positive image on the area 12a which is in coincidence with the exposed area 11a. As the trap 25' approaches the rollers 75 and 76 the excess processing liquid being spread by the rollers enters the open mouth of the trap and is collected within the trap. As the trap proper passes between the rollers the protuberances 28 at the ends of the trap separates or lifts roller 75 from roller 76 so that they will not apply pressure to the center portion of the trap and cause the excess processing fluid therein to flow back out of the mouth of the trap. As mentioned above, the trap 25 could be attached to the photosensitive layer 11' rather than the receiving layer 12', as shown. The depth of the protuberances 28 should be made just deep enough to trap all of the excess processing fluid which might be encountered and no deeper because the deeper the protuberances are the more resistance is encountered in pulling the trap between the pressure-rollers.

What is claimed is:

1. In a photographic film unit which is adapted to be processed by passing said unit between a pair of juxtaposed pressure-applying members which comprises, in combination,

a first photosensitive sheet element having a leading edge and a trailing end;

a second non-photosensitive sheet element having a leading edge and a trailing end;

a rupturable container retaining a fluid processing composition fixed to one of said sheet elements;

said sheet elements arranged for biasing into superposed relationship with said container positioned intermediate said sheet elements transversely of the leading edges thereof to effect unidirectional discharge of said containers contents between and in contact with opposed surfaces of said elements resulting from the application of compressive force to said container and said sheet elements upon movement of said film unit between and relative to said pressure-applying members; the improvement which consists of,

an elongated trailer sheet having a leading edge connected transversely to the trailing end of one of said sheet elements to form an extension thereof;

said trailer sheet medially folded back upon itself to provide a flap the free end of which will extend at least back to the trailing end of said other sheet element when said sheet elements are superposed;

said trailer sheet made from a material having sufficient rigidity and/or resilience that it resists folding so that the free end of the flap normally remains spaced from the trailer sheet to form an open mouth 0 for receiving excess processing fluid;

the longitudinal edges of said folded trailer sheet sealed together to prevent the flow of processing fluid from said edges and form an open pocket for receiving the excess processing fluid; and

at least one protuberance embossed in and extending beyond one surface of each of said sealed edges and being sufficiently non-compressible to effect a significant separation of the pressure-applying members as the trailer sheet of the film unit passes therebetween, whereby the flap of said trailer sheet will not be pressed against said trailer sheet to cause a back flow of any processing fluid which enters said pocket.

2. A photographic film unit as described in claim 1, wherein the seal between said longitudinal edges is interrupted to allow entrapped air, but not processing fluid, to escape from the pocket.

3. A photographic film unit as defined in claim ll, wherein said trailer sheet is made from a thin sheet of substantially rigid plastic material so that the free end of said flap between the sealed edges tends to bow away from said trailer sheet to form an open mouth for receiving excess processing fluid.

4. A photographic film unit as defined in claim 3,

wherein that portion of the free end of the flap between the sealed edges is scored along a line spaced from and parallel to the free end of the flap to form a bent-up lip on the flap to make the open mouth of said folded sheet funnel shaped, and wherein the longitudinal edges of said folded trailer sheet are sealed from the fold to substantially the bent-up lip of the fold.

5. A photographic film unit as defined in claim 1, wherein said first sensitive sheet element is made from a material having suiiicient rigidity and/or resilience that it resists folding, the trailing end of said first sensitive element folded transversely back upon itself, sensitive surface in, to provide a flap the free end of which will extend back beyond and engage the top surface of the trailing end of said other sheet element when said sheet elements are superposed;

the longitudinal edges of said folded-back portion of first sheet element sealed to the first sheet element to form a pocket having an open mouth for receiving the excess processing fluid and from the edges of which pocket said fluid will not escape, and

at least one protuberance embossed in and extending beyond one surface of each of said sealed edges and being sufficiently non-compressible to effect a sig nificant separation of the pressure-applying members as the trailing end of said film unit passes therebetween, whereby the folded-back end of said first sheet element will not be pressed against said film element to cause a back flow of any processing fluid which is in said pocket.

6. A photographic film unit as defined in claim 1, wherein said second non-photosensitive sheet element is made from a material having sufficient rigidity and/or resilience that it resists folding; the trailing end of said second sheet element folded transversely back upon itself to provide a flap the free end of which will extend back and engage the sensitive surface of the first sheet element when said sheet elements are brought into superposed relation; the longitudinal edges of said flap sealed to the second sheet element to form a pocket having an open mouth for receiving the excess processing fluid and from the edges of which pocket said fluid will not escape, and

at least one protuberance embossed in and extending beyond one surface of each of said sealed edges and being sufi'iciently non-compressible to effect a sig nificant separation of the pressure-applying members as the trailing end of said film unit passes therebetween, whereby the folded-back end of said second sheet element will not be pressed against said second sheet element to cause a back flow of any processing fluid which is in said pocket.

7. A photographic film unit as defined in claim 1, wherein said trailer sheet is made from a sheet of plastic material selected from the group consisting of polyesters, polystyrene and polycarbonate and having a thickness of approximately .005".

8. In an photographic film unit which is adapted to be processed by passing said unit between a pair of juxtaposed pressure-applying members which comprises, in. combination,

a sheet of film having a leading edge and a trailing end,

an image-receiving sheet having a leading edge and a trailing end,

a rupturable container retaining a fluid processing composition fixed to one of said sheets,

said film and image-receiver arranged for biasing into superposed relation with said container positioned intermediate said sheets transversely of the leading edges thereof to effect unidirectional discharge of said containers contents between and in contact with opposed surfaces of said sheets resulting from the application of compressive forces to said container and said sheets upon movement of said film unit be- 1tjween and relative to said pressure-applying memers;

a mask fixed to the surface of said image-receiving sheet spaced from the trailer sheet to form an open mouth and having a trailing end extending beyond the trailfor receiving excess processing fluid; ing end of said sheet; the longitudinal edges of said folded trailer sheet sealed spacer rails fixed to the surface of said mask and extogether to prevent the flow of processing fluid from tending along each longitudinal margin of said mask, 5 Sa edges and form an open pocket for receiving the thickness of said spacer rails in combination with eXceSS Processing fluid; and id k Spacing id superposed fil and i at least one protuberance embossed in and extending receiving sheet from one another and determining the thickness of the layer of processing fl-uid spread bebeyond one surface of each of said sealed edges and being sufiiciently non-compressible to effect a sigtween them; the improvement which consists of, 10 nificant separation of the pressure-applying members an elongated trailer sheet having a leading edge coni thg gi f g a ig E i i g nected transversely to the trailing end of said mask; g g s gg g g 2; :5 2g g g f gg i g i z g fi g gifi gfi g 2: 5;: flow of any processing fluid which enters said pocket.

by the filnlr1 Whenditth is fsuperpolsedf onh selllidfiimagefi 15 Ref e Cited receiving s eet an e ree en 0 w ic ap wi substantially abut the end of the side rails when UNITED STATES PATENTS upon the 32222 tive to and between said pressure-applying members; 20 said trailer sheet made from a material having suflicient rigidity and/or resilience that it resists folding so that the free end of the flap normally remains NORMAN G. TORCHIN, Primary Examiner J. L. GOODROW, Assistant Examiner 

